Seafloor Spreading in the Atlantic, Indian and Pacific Oceans

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image)

(Read the explanation below, while you wait for the
animation to load.)

This animation shows the breakup of Pangea and the pattern
of seafloor spreading that created the Atlantic, Indian and Pacific Oceans
during the last 150 million years. Plate tectonics is the theory that
describes how the outermost, rigid layer of the Earth has moved through
time. When plates converge they collide and a one plate dives back down
into the Earth in a region called a subduction zone. Earthquakes and
volcanoes occur in the vicinity of subduction zones. When plates move
apart, a crack or rift forms in the middle of the ocean. This rift
is sometimes also called the "mid-ocean ridge". New ocean floor
is produced at the mid-ocean ridge by a process called "sea floor
spreading". This animation shows how sea floor spreading during
the past 150 million years produced the modern ocean basins.

The colors in the animation illustrate both the age of the ocean
floor and the symmetry of sea floor spreading. The colors on either
side of the mid-ocean ridge match because the ocean floor is the same age.
As the sea floor spreads, a symmetrical rainbow-colored pattern is
produced. The colors shown in this animation roughly correspond to the
following ages of ocean floor: red - modern, orange - 20 million
years, yellow - 40 million years, light green - 60 million years, light blue -
100 million years, dark blue - 120 million years. The colors repeat once
more for older ocean floor (120 - 180 million years). These colorful
patterns were mapped by measuring the magnetic properties of the ocean
floor. Ocean floor of similar ages also have similar magnetic
patterns. These patterns are called "linear magnetic anomalies"
and formed because the Earth's magnetic field flips polarity. When the Earth's
magnetic field "flips", the north-end of a compass needle swings
around so that it points south!

You can control this animation by dragging the mouse across the
map. When you do this watch: India collide with Asia, Australia rift
away from Antarctica, and the pattern of sea floor spreading in the Pacific move
towards western North America and South America. Other animations at this
website show the evolution of each of these ocean basin in more detail ( see North
Atlantic, South Atlantic, and Pacific).

The information show in this animation was originally compiled
by researchers at the Paleoceanographic Mapping Project, University of Texas at
Austin. For more information about how these maps are made see the History
and Methods pages of this website.

This animation is available on CD-ROM in Quicktime format. For more
information see Teaching Materials.

This page uses a java applet that displays a VR model. Visit FreedomVR
at www.honeylocust.com/vr/ for more
information about this applet.